Structure of RNA-dependent RNA polymerase from 2019-nCoV, a major antiviral drug target

Gao, Yan; Yan, Liming; Huang, Yucen; Liu, Fengjiang; Zhao, Yao; Cao, Lin; Wang, Tao; Sun, Qianqian; Ming, Zhenhua; Zhang, Lianqi; Ge, Ji; Zheng, Litao; Zhang, Ying; Wang, Haofeng; Zhu, Yan; Zhu, Chen; Hu, Tianyu; Hua, Tian; Zhang, Bing; Yang, Xiuna; Li, Jun; Yang, Haitao; Liu, Zhijie; Xu, Wenqing; Guddat, Luke W.; Wang, Quan; Lou, Zhiyong; Rao, Zihe

A novel coronavirus (2019-nCoV) outbreak has caused a global pandemic resulting in tens of thousands of infections and thousands of deaths worldwide. The RNA-dependent RNA polymerase (RdRp, also named nsp12), which catalyzes the synthesis of viral RNA, is a key component of coronaviral replication/transcription machinery and appears to be a primary target for the antiviral drug, remdesivir. Here we report the cryo-EM structure of 2019-nCoV full-length nsp12 in complex with cofactors nsp7 and nsp8 at a resolution of 2.9-Å. Additional to the conserved architecture of the polymerase core of the viral polymerase family and a nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain featured in coronaviral RdRp, nsp12 possesses a newly identified β-hairpin domain at its N-terminal. Key residues for viral replication and transcription are observed. A comparative analysis to show how remdesivir binds to this polymerase is also provided. This structure provides insight into the central component of coronaviral replication/transcription machinery and sheds light on the design of new antiviral therapeutics targeting viral RdRp. One Sentence Summary Structure of 2019-nCov RNA polymerase.